Organic semiconductors continue to show promise for a variety of applications, and have been the subject of consideration for use in many low-cost, large area electronic applications. As an example, organic thin-film transistors (OTFTs) are a relatively viable alternative to more traditional, mainstream thin-film transistors (TFTs) based on inorganic materials. For organic field-effect transistors (OFETs) and other organic semiconductor devices, an important figure of merit is the charge carrier mobility μ, which is a measure of how fast charge carriers move through a semiconductor under an applied electrical field.
To suit these applications, various highly-conjugated small molecule and polymeric organic semiconductors are being researched as candidates for a variety of next generation electronic devices. However, organic semiconductor layers often exhibit relatively low mobility and, correspondingly, relatively low performance characteristics in comparison to field-effect transistors using single-crystalline inorganic semiconductors such as Silicon and Germanium and exhibiting much higher charge carrier mobilities (μ). Consequently, many electronic applications such as those requiring very high switching speeds have not typically used OTFTs.
Prior efforts to increase semiconductor mobilities and improve other processing characteristics have involved the use of some sort of passivation at the interface between dielectric layers and organic semiconductor material formed thereupon. However, these techniques have been challenging to efficiently and reproducibly implement in the manufacture of organic semiconductor devices. For instance, boundaries between crystalline grains are barriers to charge transport that can greatly reduce performance.
These and other issues have been challenging to the design, manufacture and implementation of semiconductor devices, and in particular, for those semiconductor devices employing organic semiconductor materials.